Nephrotic Syndrome FlareMANAGEMENT

GENITOURINARY AND REPRODUCTIVE PRESENTATIONS · 12 SECTIONS

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673 items

☷ Legend

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Cardiovascular Presentations71▾

Respiratory Presentations52▾

Neurological Presentations83▾

Gastrointestinal Presentations74▾

Genitourinary and Reproductive Presentations48▾

Acute Kidney Injury (ATN)Acute Kidney Injury (Post-renal)Acute Kidney Injury (Pre-renal)Amniotic Fluid Embolism Balanitis Bladder Rupture Breast Abscess Cystitis Dialysis access complications Ectopic pregnancy Epididymitis Glomerulonephritis Hematuria (gross)Hydrocele Interstitial Cystitis Mastitis Mittelschmerz Nephrolithiasis Nephrotic Syndrome Flare Nutcracker Syndrome Orchitis Ovarian Cyst Rupture Ovarian hyperstimulation syndrome Ovarian torsion Paraphimosis Pelvic Congestion Syndrome Pelvic Inflammatory Disease (PID)Peritoneal dialysis peritonitis Phimosis Priapism Prostatitis Pyelonephritis Renal laceration Renal transplant complications and rejection Ruptured ovarian cyst Testicular torsion Torsion of Appendix Testis Tubo-ovarian abscess Ureteral Rupture Urethritis Urinary Retention Urinary tract infection (uncomplicated)Urolithiasis (renal colic)Vaginal bleeding (non-pregnant)Vaginitis (Bacterial)Vaginitis (Candidal)Varicocele Vulvovaginal Hematoma

Infectious Disease Presentations148▾

Trauma Presentations89▾

Toxicologic Presentations80▾

Psychiatric Presentations26▾

Musculoskeletal and Rheumatologic Presentations96▾

Dermatology Presentations23▾

Environmental and Exposure Presentations27▾

Hematologic and Oncologic Presentations36▾

Pediatric-Specific Presentations19▾

Endocrine and Metabolic Presentations45▾

ENT and Maxillofacial Presentations27▾

Ophthalmologic Presentations19▾

Obstetric Presentations23▾

Systemic and Miscellaneous Presentations17▾

01Approach to the Critical Patient/attcp52

Immediate priorities

›Life-threatening complication recognition

›Hypovolemic shock

›SBP < 90 mmHg or MAP < 65 mmHg with severe hypoalbuminemia

›Tachycardia, cool extremities, poor skin turgor despite edema

›Intravascular depletion despite total body sodium excess

›Thromboembolic emergency

›Pulmonary embolism: acute dyspnea, pleuritic pain, tachycardia

›Cerebral venous sinus thrombosis: headache, papilledema, focal deficits

›Renal vein thrombosis: flank pain, hematuria, acute proteinuria worsening

›Spontaneous bacterial peritonitis

›Fever with abdominal pain or guarding in a nephrotic patient

›Reported in 1.5 to 16% of relapses

›Diagnostic paracentesis if ascites present with fever

›Severe AKI

›Oliguria or anuria with rising creatinine

›Risk highest in adults over 50 with severe hypoalbuminemia

›May be diuretic-induced hypovolemia or intrinsic MCD-associated AKI

Resuscitation targets

›Volume status differentiation

›Clinically overloaded but intravascularly depleted

›Avoid aggressive crystalloid; may worsen edema without restoring intravascular volume

›IV albumin 25% 1 g/kg over 2 to 4 hours for hemodynamic instability

›Monitor closely for pulmonary edema during albumin infusion

›Hemodynamic targets in shock

›MAP target > 65 mmHg

›Heart rate < 100 beats/min

›Urine output > 0.5 mL/kg/hour

02History/hx72

Presenting symptoms

›Edema pattern

›Periorbital edema: often first sign, worse in the morning

›Lower extremity pitting edema

›Scrotal or labial edema

›Ascites and abdominal distension

›Urinary symptoms

›Foamy or frothy urine: often first noticed symptom

›Decreased urine output: suggests AKI or hypovolemia

›Hematuria: suggests atypical etiology, warrants further investigation

›Constitutional symptoms

›Fatigue, malaise, weight gain over days to weeks

›Dyspnea: pleural effusion or pulmonary edema

›Abdominal pain: spontaneous bacterial peritonitis or renal vein thrombosis

Alarm features

›High-risk presentations requiring urgent evaluation

›Unilateral leg swelling with pleuritic chest pain

›DVT/PE: VTE risk up to 27% in adults with NS

›Higher risk in membranous nephropathy

›Fever with abdominal pain or guarding

›Spontaneous bacterial peritonitis: diagnostic paracentesis

›Severe headache with neurological changes

›Cerebral venous sinus thrombosis

›Posterior reversible encephalopathy syndrome (PRES) from hypertension

›Albumin < 20 to 25 g/L

›Threshold for life-threatening complications

›Life-threatening complications occur in 1 to 4% of flares at this level

Relapse characterization

›Prior disease course

›Number and timing of previous relapses

›Infrequent relapse: < 2 relapses within 6 months of initial response

›Frequent relapse: >= 2 relapses within 6 months or >= 4 per year

›Steroid-dependent: 2 consecutive relapses during steroid taper or within 14 days of stopping

›Steroid responsiveness

›Steroid-sensitive vs. steroid-resistant (no remission after 8 to 16 weeks of prednisone)

›Prior immunosuppressive agents used and response

›Cyclophosphamide, CNIs (cyclosporine/tacrolimus), MMF, rituximab

›Prior renal biopsy results: MCD, FSGS, membranous nephropathy, other

Relapse triggers and context

›Precipitating factors

›Antecedent upper respiratory infection

›Most common relapse trigger

›URI typically precedes relapse by 1 to 2 weeks

›Steroid taper or discontinuation

›Relapses commonly occur during or within 14 days of stopping steroids

›Medication non-adherence to steroids, CNIs, or MMF

›Recent infections or sick contacts

›Vaccination status: pneumococcal, meningococcal, varicella (in immunosuppressed)

Risk factors for complications

›VTE risk factors

›Albumin < 25 g/L: primary driver

›Membranous nephropathy histology: highest VTE risk

›Female sex, BMI >= 30, AKI, sepsis, immobility

›IV corticosteroid use during flare

›Lupus nephritis as underlying cause

›Infection risk factors

›Immunosuppressive therapy: steroids, CNIs, cyclophosphamide, rituximab

›Urinary losses of IgG and complement components

›Functional hyposplenism

›Asplenia or prior splenectomy

Past medical and medication history

›Comorbidities

›Diabetes mellitus: steroid-induced worsening

›Hypertension: may indicate secondary glomerulonephritis

›Thrombophilia or prior VTE episodes

›Baseline renal function and prior creatinine trajectory

›Medications contributing to or complicating NS

›NSAIDs: can cause NS (interstitial nephritis with MCD) and worsen renal function; avoid during flares

›DOACs: albumin binding leads to urinary drug loss; pharmacokinetics unreliable in NS; not recommended per KDIGO/KDOQI

›Bisphosphonates, lithium, D-penicillamine: secondary causes of NS

›Diuretics: can precipitate hypovolemia and AKI in severe hypoalbuminemia

Family and social history

›Family history

›Family history of NS or kidney disease: suggests hereditary/genetic forms

›Consanguinity: increases likelihood of monogenic NS

›Social history

›Ability to perform home urine dipstick monitoring

›Access to medications and follow-up

›Medication adherence support, particularly in pediatric patients

03Physical Exam/exam61

Vitals and general

›Hemodynamic assessment

›Blood pressure

›Hypertension: suggests secondary glomerulonephritis (lupus, MPGN)

›Hypotension: intravascular depletion despite total body fluid excess

›Heart rate

›Tachycardia: hypovolemia, infection, PE, or pain

›Temperature

›Fever: SBP, pneumonia, cellulitis, or other infection

›Hypothermia: severe sepsis marker

›Weight

›Compare to documented dry weight; quantify fluid excess in kg

Volume status exam

›Intravascular vs. total body fluid assessment

›Jugular venous pressure

›Elevated JVP with S3: suggests cardiac contribution; evaluate for heart failure overlap

›Low or flat JVP despite edema: intravascular depletion

›Mucous membranes and skin turgor

›Dry mouth and reduced skin turgor despite peripheral edema

›Capillary refill

›Prolonged > 2 seconds in hypovolemic shock

Edema distribution

›Edema pattern characterization

›Periorbital edema

›Typically worse in the morning

›Often first physical sign in children

›Lower extremity pitting edema

›Grade and extent: ankle vs. knee vs. thigh

04Differential Diagnosis/ddx41

Life-threatening diagnoses not to miss

›Pulmonary embolism

›ICD-10: I26.99

›Acute dyspnea, tachycardia, pleuritic chest pain, hypoxemia

›VTE risk up to 27% in adults with NS; highest in membranous nephropathy

›Spontaneous bacterial peritonitis

›ICD-10: K65.2

›Fever, abdominal pain, ascites in nephrotic patient

›Encapsulated organisms (Streptococcus pneumoniae, E. coli): IgG urinary loss

›Cerebral venous sinus thrombosis

›ICD-10: G08

›Headache, papilledema, focal deficits, seizures

›Consider in any nephrotic patient with new neurological symptoms

›Renal vein thrombosis

›ICD-10: N28.0

›Flank pain, gross hematuria, acute worsening proteinuria

›Most common in membranous nephropathy

Fluid overload mimics

›Heart failure

›ICD-10: I50.9

›Elevated JVP, S3, BNP elevation, pulmonary crackles

›Proteinuria typically subnephrotic (< 3.5 g/day)

›Hepatic cirrhosis

›ICD-10: K74.60

›Stigmata of liver disease, ascites predominant

›Low albumin from hepatic synthetic failure, not urinary loss

›Hypoalbuminemia from other causes

›Malnutrition, protein-losing enteropathy, chronic illness

05Laboratory Tests/lt54

First-line urinalysis

›Urinalysis with microscopy

›Dipstick proteinuria: >= 3+ confirms nephrotic-range proteinuria

›Hematuria: suggests atypical etiology; consider FSGS, lupus, MPGN

›Oval fat bodies and fatty casts: pathognomonic of heavy proteinuria

›Red blood cell casts: nephritic-nephrotic overlap; warrants biopsy

›Spot urine protein-to-creatinine ratio (uPCR)

›>= 2 g/g defines nephrotic-range proteinuria (KDIGO threshold for relapse)

›Accurate alternative to 24-hour urine collection in clinical practice

›Collect first morning void for greatest accuracy

Serum chemistries

›Basic metabolic panel

›Serum creatinine and BUN

›Baseline comparison essential; rising creatinine defines AKI

›AKI may be diuretic-induced hypovolemia or intrinsic (MCD-associated)

›Electrolytes

›Hyponatremia: exclude pseudohyponatremia from hyperlipidemia first

›Fluid restriction if true Na < 130 mmol/L

›Hypokalemia: from loop diuretic use; monitor QT interval

›Serum albumin

›< 25 g/L: significantly increases VTE risk

›< 20 g/L: life-threatening complication threshold; 1 to 4% of flares

›Severity marker driving decisions on IV albumin, anticoagulation, admission

Hematologic and coagulation tests

›Complete blood count

›Leukocytosis: infection; leukopenia if on immunosuppression

›Hemoconcentration (elevated hematocrit): intravascular depletion marker

›Thrombocytosis: reactive; increases thrombotic risk

06Diagnostic Tests/dt65

Scoring Systems

›Relapse classification (KDIGO 2021/2025)

›Remission: uPCR < 0.2 g/g or dipstick negative/trace for 3 consecutive days

›Relapse: uPCR >= 2 g/g or dipstick >= 3+ for 3 consecutive days after remission

›Infrequent relapse: < 2 relapses within first 6 months or < 4 per year

›Frequent relapse: >= 2 relapses within first 6 months or >= 4 per year

›Steroid-dependent: 2 consecutive relapses during steroid taper or within 14 days of stopping

›VTE risk assessment

›UNC Bleeding Risk Tool (med.unc.edu/gntools/bleedrisk.html)

›Weighs VTE risk against bleeding risk for anticoagulation decisions in NS

›Recommended by KDIGO 2021 for membranous nephropathy anticoagulation decisions

›Wells Score for DVT pretest probability

›Score >= 2: high probability; proceed to ultrasound

›Score < 2: low probability; D-dimer then ultrasound if positive

›PESI score for PE severity

›Class I to II: consider outpatient anticoagulation management

›Class III to V: inpatient management with close monitoring

Scoring Systems for steroid response

›Steroid resistance definition

›Children: no complete remission after 8 weeks of prednisone 60 mg/m2/day

›Adults: no complete remission after 8 to 16 weeks of prednisolone 1 mg/kg/day

›Steroid resistance triggers renal biopsy and genetic testing consideration

MRI

›MRI renal and vascular

›MR venography (MRV)

›Cerebral venous sinus thrombosis: first-line imaging when CT negative but clinical suspicion high

›Sensitivity > 90% for dural sinus thrombosis

›MRI brain with gadolinium

›Posterior reversible encephalopathy syndrome (PRES): T2/FLAIR hyperintensities in parieto-occipital regions

›Gadolinium use with caution if eGFR < 30 mL/min/1.73m2: nephrogenic systemic fibrosis risk

›MRI abdomen

›Renal vein thrombosis detection if CT contrast contraindicated

›MRA for renal artery assessment if vasculitis suspected

›CT pulmonary angiography

›Indication: suspected PE with intermediate to high clinical probability

›Sensitivity > 95%, specificity > 95% for PE

›Preferred over V/Q scan if CXR abnormal (pleural effusion, pulmonary edema)

›Contrast caution: AKI risk; weigh against diagnostic benefit

›CT abdomen with IV contrast

›Renal vein thrombosis detection: filling defect in renal vein

›Renal venous collaterals: pathognomonic of renal vein thrombosis

›Ascites characterization if SBP suspected prior to paracentesis

›CT head without contrast

›Initial imaging if cerebral venous sinus thrombosis or PRES suspected

›Normal in 30% of CVST: proceed to CT venography or MRV if normal

›CT venography

›Alternative to MRV for CVST if MRI not available

›High sensitivity for dural sinus occlusion

Ultrasound

›Renal ultrasound

›Indications: reduced eGFR, hematuria, abdominal pain, concern for structural abnormality

›Renal size: enlarged in acute NS; small and echogenic in chronic disease

›Echogenicity: increased cortical echogenicity correlates with severity

›Hydronephrosis exclusion in AKI workup

›Doppler ultrasound of renal veins

›Renal vein thrombosis: absent or reversed Doppler flow in renal vein

›Sensitivity 50 to 60% for acute renal vein thrombosis; CT or MR venography preferred

›Lower extremity venous duplex ultrasound

›DVT diagnosis: non-compressibility of vein under probe pressure

›Sensitivity 94%, specificity 98% for proximal DVT

›Repeat in 5 to 7 days if initially negative with persistent clinical suspicion

›Bedside echocardiography

›Right heart strain in massive PE: RV dilation, D-sign, TR jet velocity > 2.8 m/s

›Volume status assessment: IVC collapsibility index

›Pleural effusion quantification and guidance for thoracentesis

›Point-of-care thoracic ultrasound

›Pleural effusion: anechoic fluid above diaphragm

›Pulmonary edema: B-lines > 3 per intercostal space

›Guides therapeutic thoracentesis for respiratory distress

07Disposition/dispo35

Admission criteria

›Indications for inpatient admission

›Hemodynamic instability: hypotension, shock physiology

›IV albumin and monitoring required

›Respiratory compromise

›Massive pleural effusion, pulmonary edema, or suspected PE

›AKI

›Rising creatinine or oliguria requiring IV fluid management or nephrology

›Suspected or confirmed VTE

›DVT, PE, renal vein thrombosis, or cerebral venous sinus thrombosis

›Suspected serious infection

›SBP, sepsis, pneumonia, or invasive bacterial infection

›Severe hypoalbuminemia with limited outpatient access

›Albumin < 20 g/L with inability to ensure reliable close follow-up

›Requirement for IV diuretics or IV albumin therapy

›Severe or functionally limiting edema

›Tense ascites, respiratory compromise, or scrotal edema limiting mobility

ICU criteria

›ICU-level care triggers

›Refractory shock not responding to albumin and vasopressors

›Respiratory failure requiring mechanical ventilation or HFNC

›Massive PE with hemodynamic instability

›Severe AKI requiring renal replacement therapy

›CVST with cerebral herniation or refractory seizures

Discharge criteria

›Criteria for safe discharge

›Stable vital signs and improving edema

›Tolerating oral diuretics and corticosteroids

08Treatment/t82

Initial stabilization

›Volume management strategy

›IV albumin 25% for hypovolemia or hemodynamic instability

›Dose: 1 g/kg IV over 2 to 4 hours

›Monitor for pulmonary edema during and after infusion

›Co-administration with IV furosemide improves diuretic response in resistant edema

›Euvolemic patients with significant edema

›Loop diuretics first-line: furosemide IV 1 to 2 mg/kg or oral equivalent

›Bioavailability reduced in NS due to albumin binding in tubular lumen

›BID dosing preferred over once daily for sustained effect

Diuretic therapy

›Loop diuretics

›Furosemide IV

›Starting dose: 40 to 80 mg IV; titrate to clinical response

›Ceiling dose: 200 to 400 mg IV per dose in severe resistance

›Continuous infusion: 10 to 40 mg/hour for severe diuretic resistance

›Bumetanide IV

›1 to 2 mg IV; equivalent to furosemide 40 mg

›Better oral bioavailability than furosemide in NS

›Torsemide oral

›10 to 40 mg BID; better oral bioavailability than furosemide

›Diuretic resistance strategies

›Thiazide add-on for diuretic resistance

›Metolazone 2.5 to 10 mg oral; give 2 to 5 hours before loop diuretic

›Hydrochlorothiazide 25 to 50 mg oral as alternative

›Monitor potassium closely: high risk of hypokalemia

›Potassium-sparing diuretics

›Spironolactone 25 to 100 mg daily as adjunct

›Use cautiously if AKI or hyperkalemia risk

Immunosuppressive therapy for relapse

›Adult MCD relapse (KDIGO 2021)

›Infrequent relapse

›Prednisolone 20 to 30 mg/day until complete remission, then taper

›Lower dose than initial treatment may suffice for established MCD

›Continue until uPCR < 0.2 g/g or dipstick trace for 3 consecutive days, then taper over 3 to 6 months

›Frequent relapse or steroid-dependent disease

›Rituximab: 375 mg/m2 IV x1 to 2 doses; 2025 RCT confirmed efficacy for adult FRNS/SDNS (JAMA 2025)

›Cyclophosphamide oral: 2 mg/kg/day for 8 to 12 weeks

›Cyclosporine: 3 to 5 mg/kg/day in divided doses; target trough 100 to 150 mcg/L

›Tacrolimus: 0.05 to 0.1 mg/kg/day; target trough 4 to 8 mcg/L

›MMF: 1 to 2 g/day in divided doses

›Pediatric relapse (KDIGO 2025)

›Initial relapse treatment

›Prednisone or prednisolone 60 mg/m2/day (max 60 mg) until complete remission for >= 3 consecutive days

›Then 40 mg/m2/day alternate days (max 40 mg) for 4 weeks, then stop

›Typical response: 1 to 2 weeks in children (faster than adults)

›Frequent relapse or steroid-dependent (KDIGO 2025)

›Rituximab: preferred glucocorticoid-sparing agent per updated KDIGO 2025

›Cyclophosphamide oral: 2 to 3 mg/kg/day for 8 to 12 weeks (max cumulative dose)

›Tacrolimus vs. MMF: 2025 JAMA Pediatrics RCT showed both effective for pediatric FRNS/SDNS

›Levamisole: 2.5 mg/kg alternate days; low-cost option in resource-limited settings

›CNIs: cyclosporine or tacrolimus with regular monitoring of drug levels and renal function

Supportive pharmacotherapy

›Antiproteinuric agents

›ACE inhibitor or ARB

›Continue during relapse unless hypotensive or AKI present

›Antiproteinuric effect: 20 to 50% reduction in proteinuria

›Hold if SBP < 90 mmHg, creatinine rise > 30% from baseline, or K > 5.5 mmol/L

›Infection prophylaxis

›Trimethoprim-sulfamethoxazole prophylaxis with cyclophosphamide or high-dose steroids

›TMP-SMX single-strength daily for Pneumocystis jirovecii prophylaxis

›Antifungal prophylaxis: fluconazole if high-dose steroids and mucositis risk

›Vaccination review: pneumococcal, influenza, meningococcal (hold live vaccines during immunosuppression)

Anticoagulation for VTE

›VTE treatment

›Confirmed DVT or PE: anticoagulation required

›Unfractionated heparin IV if hemodynamically unstable PE or planned procedures

›Low molecular weight heparin (LMWH): enoxaparin 1 mg/kg SC BID (standard dosing)

›Caution: LMWH dose adjustment needed in AKI (eGFR < 30 mL/min/1.73m2); consider anti-Xa monitoring

›Warfarin: target INR 2 to 3; reliable in NS; preferred long-term agent per KDIGO

›DOACs: NOT recommended in NS due to albumin binding and unpredictable urinary drug loss (KDIGO/KDOQI)

›Duration: minimum 3 to 6 months; longer if persistent nephrotic syndrome

›VTE prophylaxis in high-risk patients

›Albumin < 25 g/L with additional risk factors: consider prophylactic anticoagulation

›Use UNC Bleeding Risk Tool to weigh thrombotic vs. bleeding risk

›Mechanical prophylaxis: compression stockings and early mobilization for all admitted patients

Diet and fluid management

›Sodium restriction

›1.5 to 2 g/day (60 to 90 mmol/day) during active flare

›Optimizes diuretic response and edema management

›Fluid restriction

›Recommended if serum Na < 130 mmol/L (after excluding pseudohyponatremia from hyperlipidemia)

›Protein intake

›Moderate protein: 0.8 to 1 g/kg/day in adults

›Excessive dietary protein does not replace urinary losses and may worsen hyperfiltration

›Lipid management

›Statin therapy for sustained hyperlipidemia during prolonged or recurrent NS

›Evidence for cardiovascular risk reduction in NS is indirect

09Special Populations/sp72

Pregnancy

›Physiologic considerations

›NS in pregnancy carries high maternal and fetal risk

›Increased risk of preeclampsia, prematurity, IUGR, and fetal loss

›Physiologic hypoalbuminemia of pregnancy complicates severity assessment

›New-onset nephrotic syndrome in pregnancy

›Must distinguish preeclampsia from primary glomerular disease

›Preeclampsia: typically after 20 weeks, hypertension, elevated liver enzymes

›Renal biopsy: deferred until postpartum if diagnosis uncertain, unless clinically urgent

›Treatment modifications in pregnancy

›Corticosteroids: prednisolone preferred over prednisone (placental metabolism reduces fetal exposure)

›Lowest effective dose; counsel on gestational diabetes risk

›ACE inhibitors and ARBs: CONTRAINDICATED in pregnancy (teratogenic)

›Use labetalol or nifedipine for hypertension management

›Cyclophosphamide: CONTRAINDICATED in all trimesters (teratogenic, mutagenic)

›Tacrolimus and cyclosporine: generally considered compatible with pregnancy with close monitoring

›MMF: CONTRAINDICATED (teratogenic); switch to azathioprine if steroid-sparing needed

›Rituximab: limited data; use only if benefit outweighs risk; avoid in first trimester

›Anticoagulation in pregnancy

›LMWH preferred over warfarin for VTE treatment in pregnancy

›Warfarin crosses placenta: teratogenic in first trimester, hemorrhagic risk in third

›Enhanced VTE prophylaxis recommended given additive thrombotic risks

Geriatric

›Age-specific considerations in older adults

›AKI risk

›Higher risk in adults > 50 with severe hypoalbuminemia and MCD

›Meyrier et al. 2018: distinct entity of acute-on-chronic kidney injury in older MCD patients

›Diuretic use

›Increased orthostatic hypotension risk; cautious up-titration required

›Higher risk of hyponatremia and hypokalemia with loop diuretics

›Infection risk

›Impaired immune response compounded by immunosuppression

›Lower threshold for blood cultures and empiric antibiotics

›Steroid side effects

›Increased risk of steroid-induced diabetes, osteoporosis, cataract, and delirium

›Bone protection: calcium + vitamin D supplementation; bisphosphonate if prolonged therapy

›Minimize cumulative steroid dose; early transition to steroid-sparing agents

›Secondary causes more common in older adults

›Membranous nephropathy: most common primary cause in adults > 50

›Malignancy-associated membranous: exclude solid tumor (lung, GI, lymphoma)

›Anti-PLA2R antibody: positive in primary membranous; negative in malignancy-associated

›Amyloidosis: AL or AA; serum/urine protein electrophoresis and fat pad biopsy

›Diabetic nephropathy: most common secondary cause globally

›Medication pharmacokinetics

›Reduced renal clearance: LMWH anti-Xa monitoring required

›CNI nephrotoxicity risk compounded by age-related GFR decline

›Polypharmacy assessment critical to avoid nephrotoxin co-administration

Pediatrics

›Epidemiology and natural history

›Peak onset: 2 to 6 years of age

›Minimal change disease accounts for > 90% of childhood NS

›80 to 90% of children with MCD are steroid-sensitive

›Approximately 50% of steroid-sensitive children develop frequently relapsing or steroid-dependent disease

›Diagnosis of relapse in children

›Urine dipstick >= 3+ for 3 consecutive days: diagnostic for relapse (KDIGO 2025)

›May be identified by parents performing home dipstick monitoring

›SBP from peritonitis: most feared acute complication; Streptococcus pneumoniae most common pathogen

›Treatment in children (KDIGO 2025)

›Relapse treatment

›Prednisone 60 mg/m2/day (max 60 mg/day) until complete remission for >= 3 days

›Then alternate-day prednisone 40 mg/m2 (max 40 mg) for 4 weeks

›Children typically respond within 1 to 2 weeks

›Steroid-sparing agents for FRNS/SDNS (KDIGO 2025 preferential order)

›Rituximab: preferred first-line steroid-sparing agent in KDIGO 2025

›Tacrolimus vs. MMF: JAMA Pediatrics 2025 RCT showed comparable efficacy for FRNS/SDNS

›Cyclophosphamide: 2 to 3 mg/kg/day for 8 to 12 weeks (track cumulative dose)

›Levamisole: 2.5 mg/kg alternate days; often used in resource-limited settings

›Weight-based dosing principles

›Furosemide: 1 to 2 mg/kg/dose IV or oral (max 40 mg initial dose in infants)

›Albumin 25%: 0.5 to 1 g/kg IV over 2 to 4 hours for hypovolemia

›LMWH: enoxaparin 1 mg/kg SC BID (neonates: 1.5 mg/kg BID); weight-based dosing tables recommended

›Growth and steroid side effects in children

›Cumulative steroid dose monitoring: impact on linear growth

›Bone mineral density: DEXA at baseline if high cumulative steroid exposure anticipated

›Ophthalmologic exam: cataracts from chronic steroid use

10Background/b62

Epidemiology

›Incidence and prevalence

›Nephrotic syndrome incidence: 2 to 7 per 100,000 adults per year

›Children: 2 to 7 per 100,000 per year; prevalence up to 16 per 100,000

›Relapse rates in MCD adults: 70 to 80% experience at least one relapse

›Average time to relapse in MCD: approximately 22 weeks after achieving remission

›Approximately 50% of steroid-sensitive children develop FRNS or steroid-dependent disease

›Histologic distribution

›Adults: membranous nephropathy most common primary cause; MCD second

›Adults > 50: membranous nephropathy and amyloidosis more prevalent; MCD less common

›Children: MCD > 90%; FSGS approximately 7 to 10%

›Steroid-resistant NS: FSGS accounts for most cases in adults

›Complication epidemiology

›VTE: approximately 27% lifetime risk in adults with NS

›SBP: 1.5 to 16% of pediatric and adult relapses

›AKI: increased risk in older adults with MCD; distinct AKI-on-MCD entity described

›Life-threatening complications during flare: 1 to 4% when albumin < 20 to 25 g/L

›Mortality

›MCD: excellent long-term prognosis with treatment; 10-year renal survival > 90%

›FSGS: more progressive; 50% 10-year renal survival without remission

›Membranous nephropathy: rule of thirds (spontaneous remission, partial remission, progression)

Pathophysiology

›Glomerular filtration barrier disruption

›Normal filtration barrier: podocytes, glomerular basement membrane (GBM), endothelium

›Podocyte injury: effacement of foot processes; critical in MCD and FSGS

›MCD: immune-mediated podocyte dysfunction; circulating permeability factors hypothesized

›Loss of anionic charge barrier allows albumin to pass into filtrate

›Consequences of massive proteinuria

›Hypoalbuminemia: urinary albumin loss exceeds hepatic synthetic capacity

›Edema formation: two mechanisms operating simultaneously

›Underfill hypothesis: reduced oncotic pressure leads to fluid extravasation; hypovolemia triggers RAAS/ADH

›Overfill hypothesis: primary renal sodium retention independent of systemic hemodynamics

›Most patients: mixed mechanism; careful volume assessment required

›Hyperlipidemia: reduced oncotic pressure stimulates hepatic lipoprotein synthesis; reduced LPL activity

›Hypercoagulability

›Urinary losses of antithrombin III, protein C, protein S, plasminogen

›Elevated fibrinogen, von Willebrand factor, and factor VIII (acute phase reactants)

›Platelet hyperactivation from hypoalbuminemia and hyperlipidemia

›Immunological basis of relapse

›T cell dysregulation: circulating permeability factors from activated T cells implicated in MCD

›B cell role: anti-PLA2R antibodies in membranous nephropathy; rituximab targets B cells

›Infection-triggered relapse: cytokine surge from URI activates T cells, precipitating podocyte injury

›Genetic susceptibility: HLA-DR7 associated with MCD in children

Therapeutic Considerations

›Steroid dosing rationale

›High-dose prednisolone induces remission in 80 to 90% of steroid-sensitive MCD

›Mechanism: anti-inflammatory and immunosuppressive; stabilizes podocyte cytoskeleton

›Adult relapse: 20 to 30 mg/day may suffice for established MCD (KDIGO 2021)

›Children: higher weight-based dosing required; 60 mg/m2/day until remission

›Steroid-sparing strategy rationale

›Cumulative steroid toxicity drives need for sparing agents

›Rituximab mechanism: depletes CD20+ B cells; reduces T cell co-stimulation indirectly

›2025 JAMA RCT: rituximab reduced relapse rate ~5-fold in adult FRNS/SDNS (Isaka et al.)

›CNI mechanism: calcineurin inhibition suppresses T cell activation; also stabilizes podocyte actin cytoskeleton

›MMF mechanism: inhibits de novo purine synthesis; selective immunosuppression of lymphocytes

›Cyclophosphamide: alkylating agent; durable remission but cumulative gonadotoxicity and malignancy risk

›Diuretic resistance mechanisms

›Hypoalbuminemia reduces tubular secretion of furosemide (albumin-bound delivery)

›Increased sodium reabsorption in distal tubule due to aldosterone activation

›Solutions: IV albumin co-infusion, BID loop diuretic dosing, sequential nephron blockade with thiazides

›Anticoagulation decision framework

›Risk-benefit analysis essential: VTE risk vs. bleeding risk

›Membranous nephropathy: VTE risk highest; anticoagulation when albumin < 25 g/L common practice

›LMWH preferred for acute VTE treatment; warfarin for long-term; DOACs unreliable due to urinary drug loss

›Antithrombin III concentrate: considered adjunct in refractory VTE with low AT-III levels (specialist decision)

11Patient Discharge Instructions/pdi37

copy discharge instructions

›Diagnosis and condition explanation

›You have been treated for a flare of nephrotic syndrome, a kidney condition causing protein to leak into the urine

›This can cause swelling, low blood protein, and increased risk of blood clots and infections

›Your kidneys are sensitive and need careful monitoring while you recover

›Medications

›Take all prescribed medications exactly as directed; do not skip or stop prednisone without your doctor's guidance

›Stopping steroids abruptly can cause serious adrenal insufficiency

›Take your diuretic (water pill) as prescribed; your doctor may adjust the dose based on your swelling and urine output

›If prescribed a blood thinner, take it exactly as directed and attend all INR checks if on warfarin

›Avoid NSAIDs (ibuprofen, naproxen, aspirin for pain): can worsen kidney function and cause further protein leak

›Avoid dehydration: drink enough fluids to maintain pale yellow urine, but restrict fluids if instructed due to low sodium

›Diet instructions

›Low-sodium diet: limit salt to 1.5 to 2 grams per day (about one teaspoon total daily)

›Avoid processed foods, canned soups, deli meats, and restaurant foods high in sodium

›Moderate protein: follow your nephrologist's recommendations; do not eat excessive protein

›Weigh yourself daily at the same time each morning before eating

›Report weight gain of more than 1 to 2 kg within 2 to 3 days to your care team

›Urine monitoring

›Check your urine with a dipstick daily until fully in remission, then at least twice per week

›A reading of 1+ or less means you may be going into remission; 3+ or 4+ means the relapse is active

›Record your results in a diary to share with your nephrologist

›Activity

›Light activity is encouraged to reduce blood clot risk; avoid prolonged immobility

›Avoid vigorous exercise until swelling and proteinuria have resolved

›Compression stockings for leg swelling if tolerated

›Infection prevention

›Wash hands frequently; avoid contact with sick individuals when on immunosuppression

12References/r40

Guidelines and key sources

›KDIGO 2025 Clinical Practice Guideline for the Management of Nephrotic Syndrome in Children

›Floege J, Gibson KL, Vivarelli M, et al. Kidney International. 2025

›URL: kdigo.org/wp-content/uploads/2025/04/KDIGO-2025-Guideline-for-Nephrotic-Syndrome-in-Children.pdf

›Defines relapse, remission, FRNS, SDNS; steroid-sparing hierarchy including rituximab as preferred first-line

›KDIGO 2021 Clinical Practice Guideline for Glomerular Diseases

›Ronco P, Rovin B, Schiandorf D, et al. Kidney International. 2021

›URL: kdigo.org/wp-content/uploads/2024/05/KDIGO-2021-Glomerular-Diseases-Guideline.pdf

›Adult NS management; VTE risk assessment; anticoagulation framework; steroid-sparing options

›KDOQI US Commentary on KDIGO 2021 Glomerular Diseases Guideline

›Beck LH, Ayoub I, Caster D, et al. American Journal of Kidney Diseases. 2023

›US-specific guidance on anticoagulation; emphasizes DOAC avoidance in NS

Landmark trials and key studies

›Rituximab for Relapsing Nephrotic Syndrome in Adults (JAMA 2025)

›Isaka Y, Sakaguchi Y, Shinzawa M, et al. Journal of the American Medical Association. 2025

›RCT confirming rituximab efficacy for adult FRNS/SDNS; approximately 5-fold relapse reduction

›Tacrolimus or Mycophenolate Mofetil for FRNS/SDNS in Children (JAMA Pediatrics 2025)

›Wang J, Liu F, Yan W, et al. JAMA Pediatrics. 2025

›Comparable efficacy of tacrolimus vs. MMF for pediatric FRNS/SDNS

›Interventions for Minimal Change Disease in Adults With Nephrotic Syndrome (Cochrane 2022)

›Azukaitis K, Palmer SC, Strippoli GF, Hodson EM. Cochrane Database Systematic Reviews. 2022

›Evidence review for steroid dosing and steroid-sparing agents in adult MCD

Secondary references

›Childhood Nephrotic Syndrome (Lancet 2023)

›Vivarelli M, Gibson K, Sinha A, Boyer O. Lancet. 2023

›PMID: 37659779

›Comprehensive pediatric NS review: epidemiology, triggers, complications, treatment

›Acute Kidney Injury Complicating Nephrotic Syndrome of Minimal Change Disease (Kidney International 2018)

Learn More: Nephrotic Syndrome Flare→

Comprehensive Clinical Review

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Reviewed by SymptomDx Medical Team · Last reviewed August 18, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.